Add some remarks about nested syntaxes to the doc

Ref #329

README.md

@@ -2,7 +2,7 @@ A Personal Wiki For Vim
 ==============================================================================
 
 ![screenshot1](doc/screenshot_1.png)
-![screenshot2](doc/screenshot_2.png)
+![screenshot2](doc/screenshot_2.png) *
 
 Intro
 ------------------------------------------------------------------------------
@@ -145,3 +145,7 @@ Add `Plugin 'vimwiki/vimwiki'` to your vimrc file and run
 Or download the [zip archive](https://github.com/vimwiki/vimwiki/archive/master.zip) and extract it in `~/.vim/bundle/`
 
 Then launch Vim, run `:Helptags` and then `:help vimwiki` to verify it was installed.
+
+----
+\* Screenshots made with the [solarized colorscheme](https://github.com/altercation/vim-colors-solarized)
+and [lightline](https://github.com/itchyny/lightline.vim)

doc/vimwiki.txt

@@ -1177,7 +1177,8 @@ This might be useful for coloring program code with external JS tools
 such as Google's syntax highlighter.
 
 You can setup Vimwiki to highlight code snippets in preformatted text.
-See |vimwiki-option-nested_syntaxes|
+See |vimwiki-option-nested_syntaxes| and
+|vimwiki-option-automatic_nested_syntaxes|.
 
 
 ------------------------------------------------------------------------------
@@ -2074,7 +2075,9 @@ Just write your preformatted text in your file like this >
  my preformatted text
  }}}
 
-where xxx is a Vim filetype.
+where xxx is a filetype which is known to Vim. For example, for C++
+highlighting, use "cpp" (not "c++"). For a list of known filetypes, type
+":setf " and hit Ctrl+d.
 
 Note that you may have to reload the file (|:edit|) to see the highlight.